Examples of the use of variable length parameters in Python? __python

Careful use of variable length parameters
Python supports variable-length parameter lists, which can be implemented by *arg, **kwargs these two special syntaxes. The following examples are used for variable length parameters:
* Use *args to implement the variable parameter list: *args with Accept
A parameter list wrapped as a tuple to pass a non-critical parameter, and the number of parameters can be arbitrary.

def sumfun (*args): Result
    = 0
    for x in args[0:]: result
      + = x return result
print Sumfun (2, 4)
pri NT Sumfun (1,2,3,4,5)
print Sumfun ()

Use **kwargs to receive a list of keyword parameters in a dictionary, where the dictionary's key-value pairs represent the parameter names and values of the mutable arguments, respectively.

def category_table (**kwargs):
    for Name, value in Kwargs.items ():
        print ' {0} is a kind of {1} '. Format (name, value) C9/>category_table (apple= ' fruit ', carrot= ' vegetable ')
category_table (BMW = ' car ')

In a function, the normal parameters, the default parameters, and the two types of variable parameters are defined.

def set_axis (x, y xlabel= ' x ', ylable= ' y ', *args, **kwargs): Pass
    

It is appropriate to use variable parameters in the following scenarios

def mydecorator (fun):
    def new (*args, **kwargs): Return
      Fun (*args, **kwargs) return
    new

If the number of parameters is indeterminate, consider using variable-length parameters.

It is used to implement the polymorphism of a function or, in the case of inheritance, some methods in which the parent class needs to be invoked.

Class A (object):
    def somefun (self, p1, p2):
        Pass
class B (a):
    def myfun (self, p3, *args, **kwargs):
        Super (B, self). Somefun (*args, **kwargs)

This digest is from the 91 recommendations for writing high-quality code to improve Python programs